As monomers for preparing ophthalmic lenses, monomers having silicon-containing groups are known. For example, 3-[tris(trimethylsiloxy)silyl]propyl methacrylate is widely used as a monomer for preparing ophthalmic lenses. The polymer obtained by copolymerizing 3-[tris(trimethylsiloxy)silyl]propyl methacrylate and N,N-dimethylacrylamide which is a hydrophilic monomer has advantageous features that it is transparent and has a high oxygen permeability. However, if a carboxylic acid such as methacrylic acid is used as a copolymerization component in order to obtain a higher moisture content, the silicone component is gradually hydrolyzed, so that the physical properties of the contact lens may be degraded when the contact lens is stored for a long period.
To solve this problem, in order to inhibit hydrolysis, 3-[tris(triethylsiloxy)silyl]propyl methacrylate described in U.S. Pat. No. 3,377,371 was prepared by reacting triethylchlorosilane and 3-trimethoxysilylpropyl methacrylate. As a result, a by-product, hexaethyldisiloxane was generated in a large amount, and the desired silicone compound was obtained with a yield of as small as several percent, which can be problematic.
Thus, conventional processes for producing silicon-containing materials typically fail to provide satisfactory yield and purity while retaining advantageous transparency and oxygen permeability. Therefore, there remains a need for methods and compositions that overcome these deficiencies and that effectively provide hydrolysis resistant silicon-containing materials.